1. Field of the Invention
This invention relates to hearing aids and in particular to improvements to the ear plug of the type of hearing aid known as a behind-the-ear (BTE) hearing aid.
2. Related Art
Various kinds of hearing aids are readily available. One of the most desirable is the "canal" hearing aid which uses miniaturized electronics and is encased in a rigid container which is inserted into the wearer's ear canal. Only a small portion of the canal aid extends outside the ear canal, including the microphone and volume adjustment devices. The battery, electronics and speaker are housed in the casing which preferably has been conformed to the shape of the ear canal for best fit. At this point it should be noted that in the hearing aid industry the speaker is called the "receiver" and thus throughout the remainder of this description the word receiver will be used to identify the speaker.
A second recognized type of hearing aid is the in-the-ear (ITE) hearing aid. This type of hearing aid is much larger than the canal aid and in addition to having a portion (including the receiver) which extends into the ear canal, also has a portion which is outside the ear canal and occupies the bowl of the ear immediately adjacent the ear canal.
In a third type of hearing aid the electronics and receiver are located remote from the ear canal and may be packaged to fit (for example) behind-the-ear (BTE). The sound is conveyed from the receiver to the ear canal by a flexible tube such as a plastic tube. One end of the tube fits over the receiver outlet of the behind-the-ear electronics package and the other end extends through an ear plug (which is hollow but otherwise shaped much like a canal hearing aid) to the interior of the ear canal. The volume control and battery are located with the BTE electronics package. In order to connect the receiver with the ear plug, the plastic tube must make a number of turns, the most severe of which is that immediately upon entering the ear plug. That turn is so sharp that the tubing frequently collapses thus reducing and distorting the internal cross section of the tubing and causing a reduction in the volume and quality of sound reaching the interior of the ear canal.